For the pizza:
- Place pizza stone in oven set to highest setting, usually about 500 degrees. Allow stone to heat for 1 hour.
- Stretch pizza dough by hand to round of desired thickness. (About ¼-inch thick with thicker edges for crust, for best results). Spread béchamel thinly across dough. Arrange spinach and ½ cup mozzarella evenly over pizza. Add pancetta and charred spring onion, distributing evenly, then top with remaining mozzarella.
- Bake pizza 8 to 12 minutes (note that time may vary slightly based on oven temperature). Cut and garnish with aged balsamic and Parmigiano.
To char the spring onions on the grill or on the stovetop, brush with oil and season. Leave them over heat until they darken, turn them over, and keep it up. There’s no need to evenly cook them—imperfections make the pizza look good, while charred bits add crunch and smoke and the less-cooked portions retain that sharp onion-y bite.
For the béchamel:
Melt butter in heavy-bottomed saucepan. Stir in flour and cook, stirring constantly, until paste cooks and bubbles a bit but doesn't brown, about 2 minutes.
Add hot milk, continuing to stir as sauce thickens. Bring to boil. Add salt and pepper to taste, lower heat, and cook, stirring for 2 to 3 minutes more. Remove from heat.
From Stage Left.